The ABEL trap is a novel device for trapping single biomolecules in solution
for extended observation. The trap estimates the position of a
fluorescently-labeled object as small as $\sim $10 nm in solution and then
applies a feedback electrokinetic drift every 20 us to trap the object by
canceling its Brownian motion. We use the ABEL trap to study HDL particles
at the single-copy level. HDL particles, essential in regulation of ``good''
cholesterol in humans, comprise a small ($\sim $10 nm) lipid bilayer disc
bounded by a belt of apolipoproteins. By engineering HDL particles with
single fluorescent donor/acceptor probes and varying lipid compositions, we
are working to study lipid diffusion on small length scales. We also use HDL
particles as hosts for single transmembrane receptors, which should enable
study of receptor conformational dynamics on long timescales.

*S.B. acknowledges an NSF Graduate Fellowship

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.MAR.C1.72